U.S. patent application number 11/709856 was filed with the patent office on 2007-07-26 for exposure apparatus and method for producing device.
This patent application is currently assigned to NIKON CORPORATION. Invention is credited to Dai Arai, Nobutaka Magome, Hiroaki Takaiwa.
Application Number | 20070171391 11/709856 |
Document ID | / |
Family ID | 32510635 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070171391 |
Kind Code |
A1 |
Magome; Nobutaka ; et
al. |
July 26, 2007 |
Exposure apparatus and method for producing device
Abstract
An exposure system includes an exposure section for irradiating
a formed resist film with exposing light through a mask with an
immersion liquid provided on the resist film, and a drying section
for drying a surface of the resist film after irradiation.
Inventors: |
Magome; Nobutaka;
(Kumagaya-shi, JP) ; Takaiwa; Hiroaki;
(Kumagaya-shi, JP) ; Arai; Dai; (Kita-ku,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
NIKON CORPORATION
TOKYO
JP
|
Family ID: |
32510635 |
Appl. No.: |
11/709856 |
Filed: |
February 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11147356 |
Jun 8, 2005 |
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11709856 |
Feb 23, 2007 |
|
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PCT/JP03/15587 |
Dec 5, 2003 |
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11147356 |
Jun 8, 2005 |
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Current U.S.
Class: |
355/53 ; 355/30;
430/322 |
Current CPC
Class: |
G03F 7/7075 20130101;
G03F 7/70341 20130101; Y10S 430/146 20130101; G03F 7/70991
20130101 |
Class at
Publication: |
355/053 ;
430/322; 355/030 |
International
Class: |
G03F 7/26 20060101
G03F007/26; G03B 27/42 20060101 G03B027/42 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2002 |
JP |
2002-357957 |
Aug 28, 2003 |
JP |
2003-305279 |
Claims
1. An exposure system comprising: an exposure section for
irradiating a formed resist film with exposing light through a mask
with an immersion liquid provided on said resist film; and a drying
section for drying a surface of said resist film after
irradiation.
2. The exposure system of claim 1, wherein said drying section
includes air blowing means.
3. The exposure system of claim 1, wherein said drying section
includes dehumidification means.
4. The exposure system of claim 1, wherein said drying section
includes warming means.
5. The exposure system of claim 1, wherein said resist film is
formed on a wafer, and said drying section dries a whole top
surface of said wafer.
6. The exposure system of claim 5, wherein said exposure section
includes twin stages having at least two wafer placing portions,
and the whole top surface of said wafer is dried on one of said
wafer placing portions of said twin stages.
7. The exposure system of claim 2, wherein said air blowing means
is an air fan capable of blowing warm air.
8. The exposure system of claim 3, wherein said dehumidification
means is a dehumidification apparatus for lowering humidity of an
environment around said resist film by using a refrigerant.
9. The exposure system of claim 3, wherein said dehumidification
means is a drying agent for lowering humidity of an atmosphere
around said resist film.
10. The exposure system of claim 4, wherein said warming means is a
warming apparatus for warming an atmosphere around said resist
film.
11. A pattern formation method comprising the steps of: forming a
resist film on a substrate; performing pattern exposure by
selectively irradiating said resist film with exposing light with
an immersion liquid provided on said resist film; removing said
immersion liquid remaining on a surface of said resist film after
the pattern exposure; and forming a resist pattern by developing
said resist film after removing said immersion liquid.
12. The pattern formation method of claim 11, wherein the step of
removing said immersion liquid is a step of blowing air against
said resist film after the pattern exposure, a step of
dehumidifying an atmosphere around said resist film after the
pattern exposure, or a step of warming said resist film after the
pattern exposure.
13. The pattern formation method of claim 11, wherein said
immersion liquid is water or perfluoropolyether.
14. The pattern formation method of claim 11, wherein said exposing
light is KrF excimer laser, Xe.sub.2 laser, ArF excimer laser,
F.sub.2 laser, KrAr laser or Ar.sub.2 laser.
15. A pattern formation method comprising the steps of: forming a
resist film on a substrate; performing pattern exposure by
selectively irradiating said resist film with exposing light with
an immersion liquid provided on said resist film; blowing air
against said resist film after the pattern exposure; and forming a
resist pattern by developing said resist film after blowing air
against said resist film.
16. A pattern formation method comprising the steps of: forming a
resist film on a substrate; performing pattern exposure by
selectively irradiating said resist film with exposing light with
an immersion liquid provided on said resist film; dehumidifying an
atmosphere around said resist film after the pattern exposure; and
forming a resist pattern by developing said resist film after
dehumidification.
17. A pattern formation method comprising the steps of: forming a
resist film on a substrate; performing pattern exposure by
selectively irradiating said resist film with exposing light with
an immersion liquid provided on said resist film; warming said
resist film after the pattern exposure; and forming a resist
pattern by developing said resist film after warming said resist
film.
18. The pattern formation method of claim 15, wherein said air is
warm air.
19. The pattern formation method of claim 15, wherein said
immersion liquid is water or perfluoropolyether.
20. The pattern formation method of claim 15, wherein said exposing
light is KrF excimer laser, Xe.sub.2 laser, ArF excimer laser,
F.sub.2 laser, KrAr laser or Ar.sub.2 laser.
21. The pattern formation method of claim 16, wherein the
atmosphere is dehumidified by using a refrigerant.
22. The pattern formation method of claim 16, wherein the
atmosphere is dehumidified by using a drying agent.
23. The pattern formation method of claim 16, wherein said
immersion liquid is water or perfluoropolyether.
24. The pattern formation method of claim 16, wherein said exposing
light is KrF excimer laser, Xe.sub.2 laser, ArF excimer laser,
F.sub.2 laser, KrAr laser or Ar.sub.2 laser.
25. The pattern formation method of claim 17, wherein said resist
film is warmed by warming an atmosphere around said resist
film.
26. The pattern formation method of claim 17, wherein said
immersion liquid is water or perfluoropolyether.
27. The pattern formation method of claim 17, wherein said exposing
light is KrF excimer laser, Xe.sub.2 laser, ArF excimer laser,
F.sub.2 laser, KrAr laser or Ar.sub.2 laser.
Description
CROSS-REFERENCE
[0001] This is a Division of application Ser. No. 11/147,356 filed
Jun. 8, 2005, which in turn is a Continuation of International
Application No. PCT/JP03/015587 filed Dec. 5, 2003 claiming the
conventional priority of Japanese patent Application Nos.
2002-357957 filed on Dec. 10, 2002 and 2003-305279 filed on Aug.
28, 2003. The disclosures of these prior applications are
incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an exposure apparatus for
exposing a substrate with a pattern image projected by a projection
optical system while filling, with a liquid, at least a part of a
space between the projection optical system and the substrate. The
present invention also relates to a liquid-removing apparatus to be
used for the exposure apparatus, and a method for producing a
device based on the use of the exposure apparatus.
[0004] 2. Description of the Related Art
[0005] Semiconductor devices and liquid crystal display devices are
produced by the so-called photolithography technique in which a
pattern formed on a mask is transferred onto a photosensitive
substrate. The exposure apparatus, which is used in the
photolithography step, includes a mask stage for supporting the
mask and a substrate stage for supporting the substrate. The
pattern on the mask is transferred onto the substrate via a
projection optical system while successively moving the mask stage
and the substrate stage. In recent years, it is demanded to realize
the higher resolution of the projection optical system in order to
respond to the further advance of the higher integration of the
device pattern. As the exposure wavelength to be used becomes
shorter, the resolution of the projection optical system is higher.
As the numerical aperture of the projection optical system becomes
larger, the resolution of the projection optical system is higher.
Therefore, the exposure wavelength, which is used for the exposure
apparatus, is shortened year by year, and the numerical aperture of
the projection optical system is increased as well. The exposure
wavelength, which is dominantly used at present, is 248 nm of the
KrF excimer laser. However, the exposure wavelength of 193 nm of
the ArF excimer laser, which is shorter than the above, is also
practically used in some situations. When the exposure is
performed, the depth of focus (DOF) is also important in the same
manner as the resolution. The resolution R and the depth of focus
.delta. are represented by the following expressions respectively.
R=k1.lamda./NA (1) .delta.=.+-.k2.lamda./NA.sup.2 (2)
[0006] In the expressions, .lamda. represents the exposure
wavelength, NA represents the numerical aperture of the projection
optical system, and k1 and k2 represent the process coefficients.
According to the expressions (1) and (2), the following fact is
appreciated. That is, when the exposure wavelength .lamda. is
shortened and the numerical aperture NA is increased in order to
enhance the resolution R, then the depth of focus 6 is
narrowed.
[0007] If the depth of focus 6 is too narrowed, it is difficult to
match the substrate surface with respect to the image plane of the
projection optical system. It is feared that the margin is
insufficient during the exposure operation. Accordingly, the liquid
immersion method has been suggested, which is disclosed, for
example, in International Publication No. 99/49504 as a method for
substantially shortening the exposure wavelength and widening the
depth of focus. In this liquid immersion method, the space between
the lower surface of the projection optical system and the
substrate surface is filled with a liquid such as water or any
organic solvent to utilize the fact that the wavelength of the
exposure light beam in the liquid is 1/n as compared with that in
the air (n represents the refractive index of the liquid, which is
about 1.2 to 1.6 in ordinary cases) so that the resolution is
improved and the depth of focus is magnified about n times.
[0008] When the substrate is subjected to the exposure process by
using the liquid immersion method, the liquid remains in some cases
on the surface of the substrate after the exposure process. If the
substrate is transported in a state in which the remaining liquid
adheres to the substrate, then the liquid falls from the substrate
during the transport, and inconveniences arise, for example, such
that respective apparatuses and members, which are disposed around
the transport passage, become rusty due to the fallen liquid,
and/or the cleanness cannot be maintained in the environment in
which the exposure apparatus is arranged. In other cases, the
environmental change (humidity change) is caused by the fallen
liquid around the exposure apparatus. If the humidity change is
caused, the following problems arise. That is, for example, any
fluctuation arises in the air on the optical path of the optical
interferometer which is to be used to measure the position of the
stage. The position of the stage is not measured accurately, and it
is impossible to obtain any desired pattern transfer accuracy.
Further, for example, if the development process is executed in a
state in which the liquid adheres to the substrate after the
exposure process, it is feared that any device having desired
performance cannot be produced.
SUMMARY OF THE INVENTION
[0009] The present invention has been made taking the foregoing
circumstances into consideration, an object of which is to provide
an apparatus which is capable of suppressing the device
deterioration caused by the liquid adhered to a substrate after the
exposure when the exposure process is performed while filling the
space between the projection optical system and the substrate with
the liquid, an exposure apparatus in which the apparatus is
incorporated, and a method for producing a device based on the use
of the exposure apparatus.
[0010] In order to solve the problems as described above, the
present invention adopts the following features.
[0011] According to a first aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0012] a projection optical system which projects the image of the
pattern onto the substrate;
[0013] a connecting section which is connected to a processing
apparatus for processing the exposed substrate; and
[0014] a liquid-removing unit which removes the liquid adhered to
the substrate before the substrate is transported to the processing
apparatus through the connecting section.
[0015] According to the present invention, the liquid-removing unit
is provided, which removes the liquid adhered to the substrate
before the substrate is transported to the processing apparatus
which performs a predetermined process for the substrate to which
the exposure process has been applied. Accordingly, the
predetermined process can be performed for the substrate in a state
in which the liquid is removed. Therefore, it is possible to
produce a device having desired performance.
[0016] According to a second aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0017] a projection optical system which projects the image of the
pattern onto the substrate;
[0018] a liquid-removing unit which removes the liquid adhered to
the substrate;
[0019] a first transport member which transports the exposed
substrate to the liquid-removing unit; and
[0020] a second transport member which transports, from the
liquid-removing unit, the substrate from which the liquid has been
removed by the liquid-removing unit.
[0021] According to the present invention, the liquid-removing unit
is provided, which removes the liquid for the exposure adhered to
the substrate after the exposure for the substrate. Therefore, it
is possible to suppress the occurrence of inconveniences which
would be otherwise caused, for example, such that the liquid falls
from the substrate during the transport of the liquid, resulting in
the environmental change. In this arrangement, the substrate, which
has been subjected to the exposure process by the liquid immersion
method and to which the liquid is adhered, can be transported to
the liquid-removing unit by the first transport member. Further,
the substrate, from which the liquid has been removed by the
liquid-removing unit, is transported by the second transport member
which is provided separately from the first transport member.
Accordingly, it is possible to transport the substrate to a
predetermined position in a state in which no liquid is adhered to
the substrate. In the present invention, it is preferable that at
least a part of a surface of the first transport member is
liquid-repellent.
[0022] According to a third aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0023] a projection optical system which projects the image of the
pattern onto the substrate;
[0024] a transport system which transports the exposed substrate;
and
[0025] a liquid-removing unit which is provided on a transport
passage for the substrate and which removes the liquid adhered to
the substrate, wherein:
[0026] the liquid-removing unit has a cover which covers at least a
part of surroundings of the substrate so that the liquid is
prevented from being scattered when the liquid is removed.
[0027] According to the present invention, the liquid-removing
unit, which removes the liquid for the exposure adhered to the
substrate, is provided at an intermediate position of the transport
passage of the transport system for transporting the substrate.
Accordingly, it is possible to simultaneously perform the exposure
process executed by the exposure apparatus (main body of exposure
apparatus) and the liquid-removing process executed by the
liquid-removing unit provided at the intermediate position of the
transport passage. Therefore, it is possible to execute the
respective processes without degrading the throughput. In this
arrangement, the liquid-removing unit is provided with the cover
which avoids the scattering of the liquid. Accordingly, it is
possible to avoid the scattering of the liquid to the surroundings
of the transport passage. Therefore, it is possible to avoid the
environmental change such as the humidity change and the occurrence
of rust or the like on the apparatus. In the present invention, it
is preferable that the cover includes a chamber.
[0028] In the exposure apparatuses according to the first to third
aspects described above, it is preferable that the liquid-removing
unit includes a washing unit which washes the substrate after the
exposure, and a washing liquid adhered to the substrate is removed
after the substrate is washed by the washing unit.
[0029] According to a fourth aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0030] a projection optical system which projects the image of the
pattern onto the substrate;
[0031] a substrate stage which holds the substrate; and
[0032] a liquid-removing unit which removes the liquid adhered to
the substrate before the exposed substrate is exported from the
substrate stage.
[0033] According to the present invention, the liquid, which is
adhered to the substrate, is removed before the substrate is
exported from the substrate stage on which the exposure process is
performed. Accordingly, it is possible to suppress the occurrence
of inconveniences which would be otherwise caused such that the
liquid falls from the substrate during the transport of the
substrate.
[0034] In the exposure apparatuses according to the first to fourth
aspects described above, it is also preferable that the substrate,
to which the liquid is adhered, is transported while being inclined
by a predetermined angle with respect to a horizontal plane after
the exposure. Further, the liquid-removing unit may remove the
liquid from the substrate by blowing off, suction, and/or
drying.
[0035] According to a fifth aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0036] a projection optical system which projects the image of the
pattern onto the substrate;
[0037] a transport system which transports the exposed substrate;
and
[0038] a liquid-processing mechanism which processes the liquid
fallen from the substrate after the exposure and which is arranged
under at least a part of a transport passage for the substrate.
[0039] According to the present invention, when the substrate after
the exposure is transported by using the transport system, even if
the liquid is adhered to the substrate, then the liquid, which has
fallen from the substrate during the transport, is processed by
using the liquid-processing mechanism, and thus it is possible to
avoid the scattering of the liquid to the surroundings of the
transport passage. Therefore, it is possible to avoid the
environmental change such as the humidity change and the occurrence
of rust or the like on the apparatus. The liquid-processing
mechanism may include a gutter member which is arranged under at
least a part of the transport passage, and a discharge mechanism
which discharges the liquid recovered by the gutter member.
[0040] According to a sixth aspect of the present invention, there
is provided an exposure apparatus for transferring an image of a
pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0041] a projection optical system which projects the image of the
pattern onto the substrate; and
[0042] a washing unit which washes the exposed substrate before the
substrate is exported to a processing apparatus which processes the
exposed substrate.
[0043] According to the present invention, foreign matters or the
like, which adhere to the surface of the substrate during the
liquid immersion exposure or during the transport of the substrate
after the exposure, can be washed out. It is possible to feed the
clean substrate. In particular, when the liquid, which is used for
the liquid immersion exposure, is a liquid other than water, for
example, any organic liquid such as cedarwood oil or fluorine-based
oil, it is desirable to remove such a liquid by using the washing
unit so as not to affect the process for the substrate to be
performed thereafter.
[0044] According to a seventh aspect of the present invention,
there is provided an exposure apparatus for transferring an image
of a pattern via a liquid onto a substrate to expose the substrate
therewith, the exposure apparatus comprising:
[0045] a projection optical system which projects the image of the
pattern onto the substrate;
[0046] a first transport member which transports the substrate to
which the liquid is adhered; and
[0047] a second transport member which transports the substrate to
which the liquid is not adhered.
[0048] According to the present invention, the first transport
member for transporting the substrate to which the liquid is
adhered and the second transport member for transporting the
substrate to which the liquid is not adhered are separately used.
Therefore, it is possible to avoid the adhesion of the liquid to
the second transport member and/or the adhesion of the liquid to
the substrate transported by the second transport member. Thus, it
is possible to suppress the diffusion and the scattering of the
liquid.
[0049] According to an eighth aspect of the present invention,
there is provided an exposure apparatus for exposing a substrate by
radiating an exposure light beam onto the substrate via a liquid,
the exposure apparatus comprising:
[0050] a first holding member which is movable while holding the
substrate;
[0051] a second holding member which is movable while holding
another substrate; and
[0052] a liquid-removing unit which removes the liquid adhered to
the substrate for which the exposure is completed and which is held
by the second holding member when the substrate, which is held by
the first holding member, is subjected to the exposure.
[0053] According to the present invention, at least parts of the
exposure process for the substrate held by one holding member and
the liquid-removing process for the substrate after the exposure
held by the other holding member are performed concurrently.
Accordingly, it is possible to suppress the decrease in the
throughput which would be otherwise accompanied by the
liquid-removing process.
[0054] According to a ninth aspect of the present invention, there
is provided a liquid-removing apparatus to be used together with an
exposure apparatus for transferring an image of a pattern via a
liquid onto a substrate to expose the substrate therewith, the
liquid-removing apparatus comprising:
[0055] a holding section which holds the exposed substrate; and
[0056] a liquid-removing mechanism which removes the liquid for the
exposure existing on the substrate.
[0057] According to a tenth aspect of the present invention, there
is provided an exposure system comprising the exposure apparatus of
the present invention; and a processing apparatus which processes
an exposed substrate. The processing apparatus may include at least
one of a coating unit which coats a base member of the substrate
with a photosensitive material, and a developing unit which
develops the exposed substrate.
[0058] The present invention provides a method for producing a
device, comprising using the exposure apparatus according to each
of the aspects described above. According to the present invention,
it is possible to suppress the change of the environment of the
exposure process resulting from the liquid adhered to the substrate
and the influence exerted on a predetermined process (for example,
the developing process) for the substrate after the exposure
process. Therefore, it is possible to produce a device having
desired performance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] FIG. 1 shows a schematic arrangement illustrating an
embodiment of a device-producing system as an exposure apparatus of
the present invention.
[0060] FIG. 2 shows a view illustrating those shown in FIG. 1 as
viewed from an upper position.
[0061] FIG. 3 shows a schematic arrangement illustrating an
embodiment of a main body of an exposure apparatus to perform the
exposure process.
[0062] FIG. 4 shows an exemplary arrangement of supply nozzles and
recovery nozzles.
[0063] FIG. 5 shows a schematic arrangement illustrating an
embodiment of a liquid-removing unit according to the present
invention.
[0064] FIG. 6 shows a schematic arrangement illustrating another
embodiment of a liquid-removing unit according to the present
invention.
[0065] FIGS. 7A and 7B show a schematic arrangement illustrating
still another embodiment of a liquid-removing unit according to the
present invention.
[0066] FIG. 8 shows a schematic arrangement illustrating still
another embodiment of a liquid-removing unit according to the
present invention.
[0067] FIG. 9 shows a schematic arrangement illustrating still
another embodiment of a liquid-removing unit according to the
present invention.
[0068] FIG. 10 shows a schematic arrangement illustrating still
another embodiment of a liquid-removing unit according to the
present invention.
[0069] FIG. 11 shows a schematic arrangement illustrating still
another embodiment of a liquid-removing unit according to the
present invention.
[0070] FIG. 12 shows a schematic arrangement illustrating still
another embodiment of a liquid-removing unit according to the
present invention.
[0071] FIG. 13 shows another embodiment of a device-producing
system as an exposure apparatus of the present invention.
[0072] FIG. 14 shows still another embodiment of a device-producing
system as an exposure apparatus of the present invention.
[0073] FIG. 15 shows a flow chart illustrating exemplary steps of
producing a semiconductor device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
First Embodiment
[0074] The exposure apparatus and the method for producing the
device according to the present invention will be explained below
with reference to the drawings. FIG. 1 shows a schematic
arrangement as viewed from a side position, illustrating an
embodiment of a device-producing system provided with an exposure
apparatus of the present invention. FIG. 2 shows a view
illustrating those shown in FIG. 1 as viewed from an upper
position.
[0075] With reference to FIGS. 1 and 2, the device-producing system
SYS includes an exposure apparatus EX-SYS and a coater-developer
apparatus C/D-SYS. The exposure apparatus EX-SYS includes an
interface section IF which forms a connecting section with respect
to the coater-developer apparatus C/D-SYS, a main body of the
exposure apparatus EX which projects an image of a pattern onto a
substrate P via a projection optical system PL and a liquid 50 to
expose the substrate P while filling the space between the
projection optical system PL and the substrate P with the liquid
50, a transport system H which transports the substrate P between
the interface section IF and the main body of exposure apparatus
EX, a liquid-removing unit 100 which is provided at an intermediate
position of a transport passage of the transport system H and which
removes the liquid adhered to the substrate P after the exposure
process, and a control unit CONT which collectively controls the
entire operation of the exposure apparatus EX-SYS. The
coater-developer system C/D-SYS includes a coating unit C which
coats a base member of the substrate P to be subjected to the
exposure process with a photoresist (photosensitive agent), and a
developing unit (processing unit) D which performs the developing
process for the substrate P after being subjected to the exposure
process performed by the main body of exposure apparatus EX. The
main body of exposure apparatus EX is arranged in a first chamber
unit CH1 in which the cleanness is managed. On the other hand, the
coating unit C and the developing unit D are arranged in a second
chamber unit CH2 which is provided separately from the first
chamber unit CH1. The first chamber unit CH1 for accommodating the
main body of exposure apparatus EX and the second chamber unit CH2
for accommodating the coating unit C and the developing unit D are
connected by the interface section IF. In the following
description, the coating unit C and the developing unit D, which
are accommodated in the second chamber unit CH2, are appropriately
referred to as "main coater-developer body C/D" in combination.
[0076] As shown in FIG. 1, the main body of exposure apparatus EX
includes an illumination optical system IL which illuminates a mask
M supported by a mask stage MST with an exposure light beam EL, a
projection optical system PL which projects an image of a pattern
of the mask M illuminated with the exposure light beam EL onto the
substrate P, and a substrate stage PST which supports the substrate
P. The main body of exposure apparatus in this embodiment adopts
the so-called twin-stage system which includes the two substrate
stages PST1, PST2. Specified constructions of the twin-stage system
are disclosed in literatures including, for example, Japanese
Patent Application Laid-open Nos. 10-163099 and 10-214783,
Published Japanese Translation of PCT International Publication for
Patent Application No. 2000-505958, and U.S. Pat. Nos. 6,341,007,
6,400,441, 6,549,269, and 6,590,634, and reference may be made
thereto. United States Patents described above are incorporated
herein by reference within a range of permission of the domestic
laws and ordinances of the state designated or selected in this
international application. In the present invention, it is possible
to adopt the twin-stage system disclosed in any one of the
literatures described above. The main body of exposure apparatus EX
in this embodiment is a scanning type exposure apparatus (so-called
scanning stepper) in which the substrate P is exposed with the
pattern formed on the mask M while synchronously moving the mask M
and the substrate P in mutually different directions (opposite
directions) in the scanning directions. In the following
explanation, the X axis direction resides in the synchronous
movement direction (scanning direction) for the mask M and the
substrate P in the horizontal plane, the Y axis direction resides
in the direction (non-scanning direction) perpendicular to the X
axis direction in the horizontal plane, and the Z axis direction
resides in the direction which is perpendicular to the X axis and
the Y axis directions and which is coincident with the optical axis
AX of the projection optical system PL. The directions about the X
axis, the Y axis, and the Z axis are designated as .theta.X,
.theta.Y, and .theta.Z directions respectively. The term
"substrate" referred to herein includes those obtained by coating a
semiconductor wafer with a resist, and the term "mask" includes a
reticle formed with a device pattern to be subjected to the
reduction projection onto the substrate.
[0077] The transport system H includes a first transport unit H1
which imports (loads) the substrate P before being subjected to the
exposure process to the substrate stage PST, a second transport
unit H2 which exports (unloads) the substrate P after being
subjected to the exposure process from the substrate stage PST and
which transports the substrate P to the liquid-removing unit 100,
and a third transport unit H3 which transports the substrate P
between the liquid-removing unit 100 and the interface section IF.
The first, second, and third transport units H1, H2, and H3 are
provided in the first chamber unit CH1. The substrate P, which is
subjected to the coating process of the photoresist by the main
coater-developer body C/D (coating unit C), is delivered to the
third transport unit H3 via the interface section IF. In this
embodiment, an opening and a shutter for opening/closing the
opening are provided at a portion of each of the first and second
chamber units CH1, CH2 to face the interface section IF. The
shutter is opened during the operation for transporting the
substrate P to the interface section IF. The third transport unit
H3 delivers the substrate P before being subjected to the exposure
process to the first transport unit H1 via the liquid-removing unit
100. When the substrate P is delivered from the third transport
unit H3 to the first transport unit H1, the substrate P may be
delivered to the first transport unit H1 via an unillustrated
another transport unit and/or a relay unit without passing through
the liquid-removing unit 100. The first transport unit H1 loads the
delivered substrate P to the substrate stage PST of the main body
of exposure apparatus EX. The substrate P after being subjected to
the exposure process is unloaded from the substrate stage PST by
the aid of the second transport unit H2. The second transport unit
H2 delivers the unloaded substrate P to the third transport unit H3
via the liquid-removing unit 100. The substrate P, which has been
transported by the third transport unit H3, is carried to the main
coater-developer body C/D (developing unit D) via the interface
section IF. The developing unit D applies the developing process to
the delivered substrate P.
[0078] The first transport unit H1, which imports the substrate P
that is not wet before being subjected to the exposure process to
the substrate stage PST, is used separately from the second
transport unit H2 which exports the substrate P that is possibly
wet after being subjected to the exposure process from the
substrate stage PST. Therefore, the liquid is not adhered to the
first transport unit (transport member) H1. It is possible to avoid
the adhesion of the liquid, for example, to the back surface of the
substrate P to be transported by the first transport unit H1.
[0079] FIG. 3 shows a schematic arrangement of the main body of the
exposure apparatus EX. The illumination optical system IL is used
so that the mask M, which is supported on the mask stage MST, is
illuminated with the exposure light beam EL. The illumination
optical system IL includes, for example, an exposure light source,
an optical integrator which uniformizes the illuminance of the
light flux radiated from the exposure light source, a condenser
lens which collects the exposure light beam EL supplied from the
optical integrator, a relay lens system, and a variable field
diaphragm which sets the illumination area on the mask M
illuminated with the exposure light beam EL to be slit-shaped. The
predetermined illumination area on the mask M is illuminated with
the exposure light beam EL having a uniform illuminance
distribution by the illumination optical system IL. Those usable as
the exposure light beam EL radiated from the illumination optical
system IL include, for example, bright lines (g-ray, h-ray, i-ray)
in the ultraviolet region radiated, for example, from a mercury
lamp, far ultraviolet light beams (DUV light beams) such as the KrF
excimer laser beam (wavelength: 248 nm), and vacuum ultraviolet
light beams (VUV light beams) such as the ArF excimer laser beam
(wavelength: 193 nm) and the F.sub.2 laser beam (wavelength: 157
nm). In this embodiment, the ArF excimer laser beam is used.
[0080] The mask stage MST supports the mask M. The mask stage MST
is two-dimensionally movable in the plane perpendicular to the
optical axis AX of the projection optical system PL, i.e., in the
XY plane, and it is finely rotatable in the .theta.Z direction. The
mask stage MST is driven by a mask stage-driving unit MSTD such as
a linear motor. The mask stage-driving unit MSTD is controlled by
the control unit CONT. The position in the two-dimensional
direction and the angle of rotation of the mask M on the mask stage
MST are measured in real-time by a laser interferometer. The result
of the measurement is outputted to the control unit CONT. The
control unit CONT drives the mask stage-driving unit MSTD on the
basis of the result of the measurement obtained by the laser
interferometer to thereby position the mask M supported on the mask
stage MST.
[0081] The projection optical system PL projects the pattern on the
mask M onto the substrate P at a predetermined projection
magnification .beta. to perform the exposure. The projection
optical system PL includes a plurality of optical elements
(lenses). The optical elements are supported by a barrel PK as a
metal member. In this embodiment, the projection optical system PL
is based on the reduction system having the projection
magnification .beta. which is, for example, 1/4 or 1/5. The
projection optical system PL may be any one of the 1.times.
magnification system and the magnifying system. Alternatively, the
projection optical system PL may be composed of mirrors. The
optical element (lens) 60 is exposed from the barrel PK on the side
of the tip (on the side of the substrate P) of the projection
optical system PL of this embodiment. The optical element 60 is
provided detachably (exchangeably) with respect to the barrel
PK.
[0082] The substrate stage PST supports the substrate P. The
substrate stage PST includes a Z stage 51 which retains the
substrate P by the aid of a substrate holder, an XY stage 52 which
supports the Z stage 51, and a base 53 which supports the XY stage
52. The substrate stage PST is driven by a substrate stage-driving
unit PSTD such as a linear motor. The substrate stage-driving unit
PSTD is controlled by the control unit CONT. When the Z stage 51 is
driven, the substrate P, which is retained on the Z stage 51, is
subjected to the control of the position (focus position) in the Z
axis direction and the positions in the .theta.X and .theta.Y
directions. When the XY stage 52 is driven, the substrate P is
subjected to the control of the position in the XY directions
(position in the directions substantially parallel to the image
plane of the projection optical system PL). That is, the Z stage 51
controls the focus position and the angle of inclination of the
substrate P so that the surface of the substrate P is adjusted to
match the image plane of the projection optical system PL in the
auto-focus manner and the auto-leveling manner. The XY stage 52
positions the substrate P in the X axis direction and the Y axis
direction. It goes without saying that the Z stage and the XY stage
may be provided as an integrated body.
[0083] A movement mirror 54 is provided on the substrate stage PST
(Z stage 51). A laser interferometer 55 is provided at a position
opposed to the movement mirror 54. The angle of rotation and the
position in the two-dimensional direction of the substrate P on the
substrate stage PST are measured in real-time by the laser
interferometer 55. The result of the measurement is outputted to
the control unit CONT. The control unit CONT drives the substrate
stage-driving unit PSTD on the basis of the result of the
measurement of the laser interferometer 55 to thereby position the
substrate P supported on the substrate stage PST.
[0084] In this embodiment, the liquid immersion method is applied
in order that the resolution is improved by substantially
shortening the exposure wavelength and the depth of focus is
substantially widened. Therefore, the space between the surface of
the substrate P and the tip surface (lower surface) 7 of the
optical element (lens) 60 of the projection optical system PL on
the side of the substrate P is filled with the predetermined liquid
50 at least during the period in which the image of the pattern on
the mask M is transferred onto the substrate P. As described above,
the lens 60 is exposed on the tip side of the projection optical
system PL, and the liquid 50 is allowed to make contact with only
the lens 60. Accordingly, the barrel PK composed of the metal is
prevented from any corrosion or the like. In this embodiment, pure
water is used for the liquid 50. The exposure light beam EL, which
is not limited to only the ArF excimer laser beam, can be
transmitted through pure water, even when the exposure light beam
EL is, for example, the bright line (g-ray, h-ray, i-ray) in the
ultraviolet region radiated, for example, from a mercury lamp or
the far ultraviolet light beam (DUV light beam) such as the KrF
excimer laser beam (wavelength: 248 nm).
[0085] The main body of the exposure apparatus EX includes a liquid
supply unit 1 which supplies the predetermined liquid 50 to the
space 56 between the substrate P and the tip surface (end surface
of the lens 60) 7 of the projection optical system PL, and a liquid
recovery unit 2 which recovers the liquid 50 from the space 56. The
liquid supply unit 1 is provided to fill at least a part of the
space between the projection optical system PL and the substrate P
with the liquid 50. The liquid supply unit 1 includes, for example,
a tank for accommodating the liquid 50, and a pressurizing pump.
One end of a supply tube 3 is connected to the liquid supply unit
1. Supply nozzles 4 are connected to the other end of the supply
tube 3. The liquid supply unit 1 supplies the liquid 50 to the
space 56 via the supply tube 3 and the supply nozzles 4.
[0086] The liquid recovery unit 2 includes, for example, a suction
pump, and a tank for accommodating the recovered liquid 50. One end
of a recovery tube 6 is connected to the liquid recovery unit 2.
Recovery nozzles 5 are connected to the other end of the recovery
tube 6. The liquid recovery unit 2 recovers the liquid 50 from the
space 56 via the recovery nozzles 5 and the recovery tube 6. When
the space 56 is filled with the liquid 50, then the control unit
CONT drives the liquid supply unit 1 so that the liquid 50, which
is in a predetermined amount per unit time, is supplied to the
space 56 via the supply tube 3 and the supply nozzles 4, and the
control unit CONT drives the liquid recovery unit 2 so that the
liquid 50, which is in a predetermined amount per unit time, is
recovered from the space 56 via the recovery nozzles 5 and the
recovery tube 6. Accordingly, the liquid 50 is arranged in the
space 56 between the substrate P and the tip surface 7 of the
projection optical system PL.
[0087] The lens 60, which is disposed at the lowest end of the
projection optical system PL, is formed to have a rectangular shape
which is long in the Y axis direction (non-scanning direction)
while remaining only the portion required for the end portion 60A
in the scanning direction. During the scanning exposure, a pattern
image of a part of the mask M is projected onto the rectangular
projection area disposed just under the end portion 60A. The mask M
is moved at the velocity V in the -X direction (or in the +X
direction) with respect to the projection optical system PL, in
synchronization with which the substrate P is moved at the velocity
.beta.V (.beta. is the projection magnification) in the +X
direction (or in the -X direction) by the aid of the XY stage 52.
After the completion of the exposure for one shot area, the next
shot area is moved to the scanning start position in accordance
with the stepping of the substrate P. The exposure process is
successively performed thereafter for each of the shot areas in the
step-and-scan manner. This embodiment is designed so that the
liquid 50 is allowed to flow in the same direction as the movement
direction of the substrate in parallel to the movement direction of
the substrate P.
[0088] FIG. 4 shows the positional relationship among the end
portion 60A of the lens 60 of the projection optical system PL, the
supply nozzles 4 (4A to 4C) for supplying the liquid 50 in the X
axis direction, and the recovery nozzles 5 (5A, 5B) for recovering
the liquid 50. In FIG. 4, the end portion 60A of the lens 60 has a
rectangular shape which is long in the Y axis direction. The three
supply nozzles 4A to 4C are arranged on the side in the +X
direction, and the two recovery nozzles 5A, 5B are arranged on the
side in the -X direction so that the end portion 60A of the lens 60
of the projection optical system PL is interposed thereby. The
supply nozzles 4A to 4C are connected to the liquid supply unit 1
via the supply tube 3, and the recovery nozzles 5A, 5B are
connected to the liquid recovery unit 2 via the recovery tube 4.
Further, the supply nozzles 8A to 8C and the recovery nozzles 9A,
9B are arranged at positions obtained by rotating, by substantially
180.degree., the positions of the supply nozzles 4A to 4C and the
recovery nozzles 5A, 5B about the center of the end portion 60A.
The supply nozzles 4A to 4C and the recovery nozzles 9A, 9B are
alternately arranged in the Y axis direction. The supply nozzles 8A
to 8C and the recovery nozzles 5A, 5B are alternately arranged in
the Y axis direction. The supply nozzles 8A to 8C are connected to
the liquid supply unit 1 via the supply tube 10. The recovery
nozzles 9A, 9B are connected to the liquid recovery unit 2 via the
recovery tube 11. The liquid is supplied from the nozzles so that
no gas portion is generated between the projection optical system
PL and the substrate P.
[0089] When the scanning exposure is performed by moving the
substrate P in the scanning direction (-X direction) indicated by
the arrow Xa (see FIG. 4) in the main body of exposure apparatus
EX, the liquid 50 is supplied and recovered with the liquid supply
unit 1 and the liquid recovery unit 2 by using the supply tube 3,
the supply nozzles 4A to 4C, the recovery tube 4, and the recovery
nozzles 5A, 5B. That is, when the substrate P is moved in the -X
direction, then the liquid 50 is supplied to the space between the
projection optical system PL and the substrate P from the liquid
supply unit 1 by the aid of the supply tube 3 and the supply
nozzles 4 (4A to 4C), and the liquid 50 is recovered to the liquid
recovery unit 2 by the aid of the recovery nozzles 5 (5A, 5B) and
the recovery tube 6. The liquid 50 flows in the -X direction so
that the space between the lens 60 and the substrate P is filled
therewith. On the other hand, when the scanning exposure is
performed by moving the substrate P in the scanning direction (+X
direction) indicated by the arrow Xb, then the liquid 50 is
supplied and recovered with the liquid supply unit 1 and the liquid
recovery unit 2 by using the supply tube 10, the supply nozzles 8A
to 8C, the recovery tube 11, and the recovery nozzles 9A, 9B. That
is, when the substrate P is moved in the +X direction, then the
liquid 50 is supplied from the liquid supply unit 1 to the space
between the projection optical system PL and the substrate P by the
aid of the supply tube 10 and the supply nozzles 8 (8A to 8C), and
the liquid 50 is recovered to the liquid recovery unit 2 by the aid
of the recovery nozzles 9 (9A, 9B) and the recovery tube 11. The
liquid 50 flows in the +X direction so that the space between the
lens 60 and the substrate P is filled therewith. As described
above, the control unit CONT allows the liquid 50 to flow in the
movement direction of the substrate P by using the liquid supply
unit 1 and the liquid recovery unit 2. In this arrangement, for
example, the liquid 50, which is supplied from the liquid supply
unit 1 via the supply nozzles 4, flows so that the liquid 50 is
attracted and introduced into the space 56 in accordance with the
movement of the substrate P in the -X direction. Therefore, even
when the supply energy of the liquid supply unit 1 is small, the
liquid 50 can be supplied to the space 56 with ease. When the
direction, in which the liquid 50 is allowed to flow, is switched
depending on the scanning direction, then it is possible to fill
the space between the substrate P and the tip surface 7 of the lens
60 with the liquid 50, and it is possible to obtain the high
resolution and the wide depth of focus, even when the substrate P
is subjected to the scanning in any one of the +X direction and the
-X direction.
[0090] Next, an explanation will be made with reference to FIG. 5
about the liquid-removing unit 100 to be used for the exposure
apparatus of the first embodiment. The liquid-removing unit 100 is
provided at an intermediate position of the transport passage of
the transport system H, and it removes the liquid 50 adhered to the
substrate P after being subjected to the exposure process in
accordance with the liquid immersion method. In this embodiment,
the liquid-removing unit 100 is provided between the second
transport unit H2 and the third transport unit H3. The
liquid-removing unit 100 includes a stage unit 20, a holder 21
which is provided on the stage unit 20 and which holds a lower
surface central portion of the substrate P, and a rotating
mechanism 22 which rotates the holder 21 that holds the substrate
P. A vacuum attraction hole, which constitutes a part of a vacuum
unit, is provided through the upper surface of the holder 21. The
holder 21 attracts and holds the lower surface central portion of
the substrate P. The rotating mechanism 22 is constructed by a
motor which is provided in the stage unit 20. The rotating
mechanism 22 rotates the holder 21 by rotating a shaft 23 which is
connected to the holder 21. The stage unit 20, the holder 21, and
the rotating mechanism 22 are provided in a chamber 25 which serves
as a cover mechanism. A liquid-sucking unit 29 is provided for the
chamber 25 via a flow passage 28. The flow passage 28 is provided
with a valve 28A.
[0091] The holder 21 is provided movably upwardly and downwardly
with respect to the upper surface of the stage unit 20 together
with the shaft 23. When the holder 21, which holds the substrate P,
is moved upwardly with respect to the stage unit 20, then the
substrate P is separated from the stage unit 20, and the substrate
P is movable in accordance with the driving of the rotating
mechanism 22. On the other hand, when the holder 21 is moved
downwardly, the substrate P is retained by a second holder 24 which
is provided on the upper surface of the stage unit 20.
[0092] The chamber 25 is provided with a first opening 26 which is
formed on the side of the second transport unit H2, and a second
opening 27 which is formed on the side of the third transport unit
H3. A first shutter 26A, which opens/closes the first opening 26,
is provided for the first opening 26. A second shutter 27A, which
opens/closes the second opening 27, is provided for the second
opening 27. The opening/closing operations of the first and second
shutters 26A, 27A are controlled by the control unit CONT. When the
first shutter 26A is opened, the second transport unit H2 is
accessible to the stage unit 20 of the liquid-removing unit 100 via
the first opening 26. That is, the second transport unit H2 is
capable of transporting (importing) the substrate P to the stage
unit 20 of the liquid-removing unit 100 via the first opening 26.
The third transport unit H3 is accessible to the stage unit 20 of
the liquid-removing unit 100 via the second opening 27. That is,
the third transport unit H3 is capable of transporting (exporting)
the substrate P to the stage unit 20 of the liquid-removing unit
100 via the second opening 27. On the other hand, when the first
and second shutters 26A, 27A are closed, the interior of the
chamber 25 is tightly closed.
[0093] Next, an explanation will be made with reference to FIGS. 1
and 2 about the operation of the device-producing system SYS
provided with the main body of the exposure apparatus EX and the
liquid-removing unit 100 described above.
[0094] The substrate P, which is held by the substrate stage PST1
in the main body of exposure apparatus EX, is subjected to the
exposure by using the liquid immersion method, concurrently with
which the alignment mark is detected and the surface information
(AF (autofocus)/AL (autoleveling) information) is measured for the
substrate P retained by the substrate stage PST2. FIG. 1 shows a
situation in which the substrate stage PST1 performs the exposure
operation in the main body of exposure apparatus (exposure station)
EX, and the substrate stage PST2 performs the measuring operation
in the measuring station. In the main body of exposure apparatus,
the liquid is supplied by the liquid supply unit 1, and the liquid
is recovered by the liquid recovery unit 2. The optical path for
the exposure light beam, which is disposed on the image plane side
of the projection optical system PL, is filled with the liquid 50.
When the exposure process is completed for the substrate P retained
by the substrate stage PST1, then the liquid supply by the liquid
supply unit 1 is stopped, and the liquid recovery is performed by
the liquid recovery unit 2. When the liquid recovery by the liquid
recovery unit 2 is completed, then the substrate stage PST1 is
retracted from the main body of exposure apparatus EX, and the
substrate stage PST2, for which the various measurements have been
completed, is introduced into the main body of exposure apparatus
(exposure station) EX. The substrate P, for which the exposure
process is completed on the substrate stage PST1, is unloaded from
the substrate stage PST1 to the second transport unit H2. The
substrate stage PST1, from which the substrate P is completely
unloaded after the exposure process, receives the unexposed
substrate P from the first transport unit H1 to start the various
measurements on the measuring station. A slight amount of the
liquid 50, which is not completely recovered by the liquid recovery
unit 2, adheres to the substrate P unloaded to the second transport
unit H2. The substrate P is transported to the liquid-removing unit
100 by the second transport unit H2. Thus, the liquid-removing unit
100 removes the liquid remaining on the substrate P for which the
exposure process has been just completed, concurrently with the
exposure process for the substrate P retained by the substrate
stage PST2 and the various measurements for the substrate P
retained by the substrate stage PST1.
[0095] When the supply of the liquid is started from the liquid
supply unit 1 onto the substrate P retained on the substrate stage
PST2, then the substrate stage PST1 may be only moved without
performing any substantial measuring operation with the substrate
stage PST1, or the substrate stage PST1 may be simply stopped. By
doing so, it is possible to avoid the influence on the measuring
operation for the substrate stage PST1 in the measuring station,
which would be otherwise exerted by the vibration generated when
the supply of the liquid is started from the liquid supply unit 1
onto the substrate stage PST2. When the supply of the liquid onto
the substrate stage PST2 is stopped, if the measuring operation for
the substrate stage PST1 has not been completed in the measuring
station, then the substrate stage PST1 may be only moved, or the
substrate stage PST1 may be simply stopped, without performing any
substantial measuring operation for the substrate stage PST1 when
the supply of the liquid is stopped.
[0096] The control unit CONT opens the first shutter 26A as the
second transport unit H2 approaches the liquid-removing unit 100
(see FIG. 5). In this situation, the second shutter 27A is closed.
The second transport unit H2 delivers the substrate P to the stage
unit 20 of the liquid-removing unit 100 via the first opening 26.
In this situation, the holder 21 is moved downwardly, and the
substrate P is retained by the holder 21 and the second holder 24
on the stage unit 20.
[0097] After the second transport unit H2 delivers the substrate P
to the stage unit 20, the second transport unit H2 is retracted
from the chamber 25 via the first opening 26. When the second
transport unit H2 is retracted from the chamber 25, the control
unit CONT closes the first shutter 26A. Accordingly, the interior
of the chamber 25 is tightly closed. When the interior of the
chamber 25 is tightly closed, the control unit CONT moves the
holder 21 upwardly. As the holder 21 is moved upwardly, the
substrate P, which is attracted and retained by the holder 21, is
also moved upwardly with respect to the stage unit 20. The control
unit CONT drives the rotating mechanism 22 to rotate the holder 21
in the .theta.Z direction together with the substrate P. As the
rotating mechanism 22 rotates the substrate P, the liquid 50, which
is adhered to the both upper and lower surfaces of the substrate P,
blown off from the substrate P in accordance with the action of the
centrifugal force. Accordingly, the liquid 50, which is adhered to
the substrate P, is removed from the substrate P. In this
arrangement, the substrate P is arranged in the chamber 25 which
serves as the cover mechanism. Therefore, the liquid 50, which is
blown off from the substrate P, is not scattered to the
surroundings.
[0098] The liquid 50, which is blown off from the substrate P, is
recovered by the liquid-sucking unit 29 which is connected to the
chamber 25. The liquid-sucking unit 29 recovers the liquid 50 blown
off from the substrate P by sucking the gas contained in the
chamber 25 together with the scattered liquid 50. In this
procedure, the liquid-sucking unit 29 continuously performs the
operation for sucking the gas contained in the chamber 25 and the
scattered liquid 50. Accordingly, the liquid 50 does not stay in
the chamber 25 including, for example, the inner wall and the
bottom of the chamber 25. Therefore, the humidity in the chamber 25
is not greatly varied. Any wet gas contained in the chamber 25 does
not outflow to the outside of the chamber 25, when the shutters
26A, 27A are opened as well.
[0099] When the substrate P is rotated for a predetermined period
of time (or by a predetermined number of revolutions), then the
control unit CONT stops the driving of the rotating mechanism 22,
and the substrate P is moved downwardly together with the holder
21. Subsequently, the control unit CONT opens the second shutter
27A. When the second shutter 27A is opened, the third transport
unit (second transport member) H3 makes the access to the stage
unit 20 via the second opening 27 to retain the substrate P which
is disposed on the stage unit 20 and from which the liquid 50 has
been removed. The third transport unit H3, which retains the
substrate P from which the liquid 50 has been removed by the
liquid-removing unit 100, exports the substrate P from the interior
of the chamber 25 via the second opening 27.
[0100] As shown in FIG. 1, the substrate P, from which the liquid
50 has been removed by the liquid-removing unit 100, is carried to
the main coater-developer body C/D through the interface section
IF. The main coater-developer body C/D (developing unit D) applies
the developing process to the delivered substrate P. As described
above, the exposure apparatus EX-SYS of this embodiment removes the
liquid 50 adhered to the substrate P by the liquid-removing unit
100 before the substrate P is transported to the coater-developer
apparatus CD-SYS through the interface section IF.
[0101] As explained above, the liquid 50, which is adhered to the
substrate P, is removed by the liquid-removing unit 100 before the
substrate P, to which the exposure process has been applied by the
main body of exposure apparatus EX, is transported to the
coater-developer apparatus C/D-SYS (developing unit D). Therefore,
it is possible to exclude the influence of the liquid 50 on the
developing process. When the liquid 50, which is adhered to the
substrate P, is removed by the liquid-removing unit 100, it is
possible to suppress the occurrence of inconveniences which would
be otherwise caused, for example, such that the liquid falls from
the substrate P during the transport of the substrate P, the
humidity change (environmental change) is caused in the first
chamber unit CH1, and the rust appears on the members and the
respective units or apparatuses disposed on the transport
passage.
[0102] The substrate P, to which the liquid 50 is adhered, is
transported by the second transport unit H2, and the substrate P,
from which the liquid 50 has been removed, is transported by the
third transport unit H3 which is provided separately from the
second transport unit H2. Therefore, the third transport unit H3 is
not exposed to the liquid 50. Therefore, the liquid 50 is not
adhered to the substrate P which is transported by the third
transport unit H3. Further, it is possible to reliably avoid the
scattering of the liquid 50 on the transport passage of the third
transport unit H3.
[0103] The liquid-removing unit 100 is provided at the intermediate
position of the transport passage of the transport system H.
Therefore, it is possible to simultaneously perform the exposure
process with the main body of exposure apparatus EX and the
liquid-removing process with the liquid-removing unit 100.
Therefore, it is possible to execute the respective processes
without degrading the throughput. Further, the liquid-removing
process is performed in the chamber 25. Therefore, it is possible
to avoid the scattering of the liquid 50 to the surroundings.
[0104] This embodiment has been explained such that the transport
is performed via the interface section IF as the connecting section
when the substrate P after the exposure process is transported to
the coater-developer apparatus C/D-SYS as the processing apparatus.
However, the opening of the first chamber unit CH1 serves as the
connecting section for the exposure apparatus EX-SYS, for example,
when the interface section IF is provided for the coater-developer
apparatus C/D-SYS, when the coater-developer apparatus C/D-SYS is
directly connected to the exposure apparatus EX-SYS without using
the interface section IF, or when the processing apparatus is a
substrate-accommodating apparatus, and the substrate P after the
exposure process is transported to the substrate-accommodating
apparatus without using the interface section IF.
[0105] As described above, the liquid 50 is composed of pure water
in this embodiment. Pure water is advantageous in that pure water
is available in a large amount with ease, for example, in the
semiconductor production factory, and pure water exerts no harmful
influence, for example, on the optical element (lens) and the
photoresist on the substrate P. Further, pure water exerts no
harmful influence on the environment, and the content of impurity
is extremely low. Therefore, it is also expected to obtain the
function to wash the surface of the substrate P and the surface of
the optical element provided at the tip surface of the projection
optical system PL.
[0106] It is approved that the refractive index n of pure water
(water) with respect to the exposure light beam EL having a
wavelength of about 193 nm is approximately in an extent of 1.44 to
1.47. When the ArF excimer laser beam (wavelength: 193 nm) is used
as the light source of the exposure light beam EL, then the
wavelength is shortened on the substrate P by 1/n, i.e., to about
131 to 134 nm, and a high resolution is obtained. Further, the
depth of focus is magnified about n times, i.e., about 1.44 to 1.47
times as compared with the value obtained in the air. Therefore,
when it is enough to secure an approximately equivalent depth of
focus as compared with the case of the use in the air, it is
possible to further increase the numerical aperture of the
projection optical system PL. Also in this viewpoint, the
resolution is improved.
[0107] In this embodiment, the lens 60 is attached to the tip of
the projection optical system PL. However, the optical element,
which is attached to the tip of the projection optical system PL,
may be an optical plate which is usable to adjust the optical
characteristics of the projection optical system PL, for example,
the aberration (for example, spherical aberration and comatic
aberration). Alternatively, the optical element may be a parallel
plane plate through which the exposure light beam EL is
transmissive. When the optical element, which makes contact with
the liquid 50, is the parallel plane plate which is cheaper than
the lens, it is enough that the parallel plane plate is merely
exchanged immediately before supplying the liquid 50 even when any
substance (for example, any silicon-based organic matter), which
deteriorates the transmittance of the projection optical system PL,
the illuminance of the exposure light beam EL on the substrate P,
and the uniformity of the illuminance distribution, is adhered to
the parallel plane plate, for example, during the transport, the
assembling, and/or the adjustment of the exposure apparatus EX. An
advantage is obtained such that the exchange cost is lowered as
compared with the case in which the optical element to make contact
with the liquid 50 is the lens. That is, the surface of the optical
element to make contact with the liquid 50 is dirtied, for example,
due to the adhesion of scattered particles generated from the
resist by being irradiated with the exposure light beam EL or any
impurity contained in the liquid 50. Therefore, it is necessary to
periodically exchange the optical element. However, when the
optical element is the cheap parallel plane plate, then the cost of
the exchange part is low as compared with the lens, and it is
possible to shorten the time required for the exchange. Thus, it is
possible to suppress the increase in the maintenance cost (running
cost) and the decrease in the throughput.
[0108] When the pressure, which is generated by the flow of the
liquid 50, is large between the substrate P and the optical element
disposed at the tip of the projection optical system PL, it is also
allowable that the optical element is tightly fixed so that the
optical element is not moved by the pressure, without allowing the
optical element to be exchangeable.
[0109] This embodiment is constructed such that the space between
the projection optical system PL and the surface of the substrate P
is filled with the liquid 50. However, the space may be filled with
the liquid 50, for example, in a state in which a cover glass
composed of a parallel plane plate is attached to the surface of
the substrate P.
[0110] In the embodiment described above, the shape of the nozzle
is not specifically limited. For example, the liquid 50 may be
supplied or recovered by using two pairs of nozzles for the long
side of the end portion 60A. In this arrangement, the supply
nozzles and the recovery nozzles may be arranged and aligned
vertically in order to supply and recover the liquid 50 from any
one of the directions of the +X direction and the -X direction.
Second Embodiment
[0111] Next, an explanation will be made with reference to FIG. 6
about a liquid-removing unit 100 to be used for an exposure
apparatus according to a second embodiment of the present
invention. In the following explanation, those other than the
liquid-removing unit 100 are the same as or equivalent to those of
the first embodiment, any explanation of which will be simplified
or omitted.
[0112] With reference to FIG. 6, the liquid-removing unit 100
includes a cover 30 which constitutes a part of a cover mechanism
for covering the surroundings of the substrate P so that the liquid
50 is not scattered when the liquid 50 adhered to the substrate P
is removed. In this embodiment, the liquid-removing unit 100 does
not have the chamber 25. The cover 30 is formed to be approximately
annular as viewed in a plan view. The cover 30 has a pocket 30A
provided in the annular section. The liquid-sucking unit 29 is
connected to the pocket 30A of the cover 30. The cover 30 can be
arranged in a recess 31 which is formed in the stage unit 20. The
cover 30 is movable upwardly and downwardly (capable of protruding
and retracting) with respect to the stage unit 20 by the aid of a
lifting mechanism 32. When the liquid-removing process is
performed, the cover 30 is also moved upwardly together with the
upward movement of the holder 21. The cover 30 is provided to cover
the surroundings of the substrate P. Therefore, the liquid 50,
which is blown off by the rotation of the substrate P, is recovered
by the pocket 30A of the cover 30. The liquid 50, which is
recovered by the pocket 30A, is recovered by the liquid-sucking
unit 29.
[0113] As explained above, the cover 30, which covers the
surroundings of the substrate P, can be also used as the cover
mechanism. Accordingly, it is possible to avoid the scattering of
the liquid 50 to the surroundings by the simple structure as
compared with the chamber 25 explained in the first embodiment.
Third Embodiment
[0114] Next, an explanation will be made with reference to FIG. 7
about a liquid-removing unit 100 to be used for an exposure
apparatus according to a third embodiment. This embodiment is
characterized in that the rotating mechanism 22 and the cover 30,
which constitute the liquid-removing unit 100, are provided in a
substrate stage PST of a main body of exposure apparatus EX for
performing the exposure process. The structure of the main body of
the exposure apparatus EX is equivalent to that described in the
first embodiment, any explanation of which will be omitted.
[0115] With reference to FIG. 7A, the substrate stage PST includes
the holder 21 and the second holder 24 for supporting the substrate
P, and a recess 31 capable of accommodating the cover 30. As shown
in FIG. 7A, the image of the pattern is transferred via the
projection optical system PL and the liquid 50 onto the substrate P
retained by the holder 21 and the second holder 24. When the
exposure process is completed for the substrate P, then the control
unit CONT stops the supply of the liquid 50 from the liquid supply
unit 1 to the space between the projection optical system PL and
the substrate P, and the liquid 50 on the substrate P is recovered
by the liquid recovery unit 2 as shown in FIG. 7B. When the
recovery operation is completed, the substrate stage PST is
retracted from the position just under the projection optical
system PL. Subsequently, the control unit CONT upwardly moves the
holder 21 which retains the substrate P, and the control unit CONT
upwardly moves the cover 30. The control unit CONT drives the
rotating mechanism 22 to rotate the substrate P. Accordingly, the
liquid 50, which is adhered to the substrate P as a result of any
incomplete recovery by the liquid recovery unit 2, is removed from
the substrate P. After the liquid 50 adhered to the substrate P is
removed, the second transport unit H2 exports the substrate P from
the substrate stage PST.
[0116] As explained above, the liquid-removing unit 100 can be also
provided in the substrate stage PST. When the liquid adhered to the
substrate P is removed before the substrate P is exported from the
substrate stage PST on which the exposure process is performed, it
is possible to suppress the occurrence of any inconvenience which
would be otherwise caused such that the liquid 50 falls from the
substrate P during the transport of the substrate P. In this
embodiment, the main body of exposure apparatus EX adopts the
twin-stage system. Therefore, it is possible to simultaneously
perform the exposure process on the first substrate stage PST1 and
the liquid-removing process on the second substrate stage PST2. It
is possible to execute the entire process without degrading the
throughput.
[0117] The third embodiment adopts the mechanism for rotating the
substrate P in order to remove the liquid adhered to the substrate
P before the substrate P after the exposure process is transported
from the substrate stage PST. Alternatively, it is also allowable
to provide a blower to blow off the liquid. Further alternatively,
it is also allowable to provide a mechanism for sucking the
remaining liquid on the substrate P separately from the liquid
recovery unit 2. These alternatives may be used in combination.
Fourth Embodiment
[0118] Next, an explanation will be made with reference to FIG. 8
about a liquid-removing unit 100 to be used for an exposure
apparatus according to a fourth embodiment. The liquid-removing
unit 100 shown in FIG. 8 is provided between the second transport
unit H2 and the third transport unit H3 at an intermediate position
of the transport passage of the transport system H, and includes a
chamber 25. The structure of the main body of the exposure
apparatus EX is equivalent to that described in the first
embodiment, any explanation of which will be omitted.
[0119] With reference to FIG. 8, the liquid-removing unit 100
includes a first blow section 33 which allows the gas to blow
against the front surface (upper surface) of the substrate P to
remove the liquid 50 by blowing off the liquid 50 adhered to the
front surface of the substrate P, and a second blow section 34
which allows the gas to blow against the back surface (lower
surface) of the substrate P to remove the liquid 50 by blowing off
the liquid 50 adhered to the back surface of the substrate P. The
first and second blow sections 33, 34 are connected to a gas supply
unit 35 via flow passages respectively. A filter is provided in
each of the flow passages to remove foreign matters (dust and oil
mist) contained in the gas to be blown against the substrate P. The
gas supply unit 35 supplies the dry gas to the first and second
blow sections 33, 34. In this embodiment, the gas supply unit 35
supplies the dry air.
[0120] FIG. 9 shows a view in which the interior of the chamber 25
shown in FIG. 8 is viewed from an upper position. As shown in FIG.
9, the substrate P is held by a holding unit 36 at both ends in the
Y axis direction of the lower surface thereof (holding unit 36 is
not shown in FIG. 8). The substrate P is delivered to the holding
unit 36 from the second transport unit H2, and the holding unit 36
holds the delivered substrate P. It is arranged that the substrate
P, which is held by the holding unit 36, is delivered to the third
transport unit H3. The first blow section 33 includes a nozzle main
section 33A which has a longitudinal direction thereof in the Y
axis direction, and a plurality of nozzle holes 33B which are
provided and aligned in the longitudinal direction of the nozzle
main section 33A. The dry air, which is supplied from the gas
supply unit 35, is blown from the plurality of nozzle holes 33B
respectively. The second blow section 34 is also constructed
equivalently to the first blow section 33, which includes a nozzle
main section having a longitudinal direction thereof in the Y axis
direction, and a plurality of nozzle holes.
[0121] The substrate P held by the holding unit 36 and the first
and second blow sections 33, 34 are provided relatively movably. In
this embodiment, the first and second blow sections 33, 34 make
scanning movement in the X axis direction with respect to the
substrate P held by the holding unit 36. Alternatively, a driving
unit may be provided for the holding unit 36 to move the substrate
P with respect to the first and second blow sections 33, 34.
Further alternatively, both of the first and second blow sections
33, 34 and the holding unit 36 may be moved.
[0122] Next, an explanation will be made about the operation of the
liquid-removing unit 100 constructed as described above. The second
transport unit H2 delivers, to the holding unit 36, the substrate P
to which the liquid 50 is adhered. The control unit CONT allows the
gas to blow from the first and second blow sections 33, 34 against
the substrate P held by the holding unit 36. In this embodiment,
the gas, which is supplied from the first and second blow sections
33, 34, is blown in the inclined directions with respect to the
front and back surfaces of the substrate P. The control unit CONT
allows the gas to blow against the substrate P held by the holding
unit 36 while moving the first and second blow sections 33, 34 in
the X axis direction. In this embodiment, the length of the nozzle
main section of each of the first and second blow sections 33, 34
is sufficiently larger than that of the substrate P. Therefore, the
gas is blown uniformly against the entire front and back surfaces
of the substrate P. When the gas is blown out, the liquid 50, which
is adhered to the substrate P, is blown off and removed. The liquid
50, which has been blown off, is recovered by the liquid-sucking
unit 29. The substrate P, from which the liquid 50 has been
removed, is delivered to the third transport unit H3.
Fifth Embodiment
[0123] Next, an explanation will be made with reference to FIG. 10
about a liquid-removing unit 100 to be used for an exposure
apparatus according to a fifth embodiment. With reference to FIG.
10, the liquid-removing unit 100 includes first and second sucking
sections 37, 38 which are connected to the liquid-sucking unit 29
via flow passages and which suck the liquid 50 adhered to the front
surface and the back surface of the substrate P respectively, and a
drying unit 39 which dries the interior of the chamber 25. The
first and second sucking sections 37, 38 are provided relatively
movably in the X axis direction with respect to the substrate P.
When the liquid 50 adhered to the substrate P is removed, the
control unit CONT drives the liquid-sucking unit 29 in a state in
which the first and second sucking sections 37, 38 approach the
substrate P. Accordingly, the liquid 50, which is adhered to the
substrate P, is sucked into the liquid-sucking unit 29 by the aid
of the first and second sucking sections 37, 38. The sucking
operation is performed by the liquid-sucking unit 29 while moving
the first and second sucking sections 37, 38 in the X direction
with respect to the substrate P, and thus the liquid 50 adhered to
the substrate P is removed. In this procedure, the drying unit 39
supplies the dry gas (dry air) into the chamber 25. The interior of
the chamber 25 is dried by the driving of the drying unit 39.
Accordingly, it is possible to facilitate the removal of the liquid
50 from the substrate P. The structure of the main body of the
exposure apparatus EX is equivalent to that described in the first
embodiment, any explanation of which will be omitted.
[0124] It is also allowable to simultaneously execute the sucking
operation for sucking the liquid 50 on the substrate P as explained
with reference to FIG. 10 and the gas-blowing operation from the
blow sections as explained with reference to FIG. 8. Alternatively,
any one of the sucking operation and the gas-blowing operation may
be executed, and the other may be executed thereafter. The drying
operation by the drying unit 39 may be performed concurrently as
well. The drying operation may be also performed before and/or
after the sucking operation and/or the gas-blowing operation. That
is, it is possible to appropriately combine and execute the sucking
operation, the drying operation, and the gas-blowing operation
(liquid-blowing off operation).
Sixth Embodiment
[0125] Next, an explanation will be made with reference to FIG. 11
about a liquid-removing unit 100 of an exposure apparatus according
to a sixth embodiment. The structure of the main body of the
exposure apparatus EX is equivalent to that described in the first
embodiment, any explanation of which will be omitted. With
reference to FIG. 11, the liquid-removing unit 100 includes first
and second blow sections 33, 34, and a chamber 40 which
accommodates the first and second blow sections 33, 34. In this
embodiment, the chamber 40 is provided with first and second
openings 41, 42 which are formed by being deviated in the Z axis
direction. In this embodiment, no shutter is provided for the first
and second openings 41, 42. However, it is also possible to provide
shutters respectively. In this embodiment, a second transport unit
H2 includes an arm (first transport member) 43 which is capable of
inserting the substrate P into the chamber via the first opening 41
while holding the substrate P. The arm 43 transports the substrate
P to which the liquid 50 is adhered after the exposure process
performed by the liquid immersion method in a state in which the
substrate P is inclined by a predetermined angle with respect to
the horizontal plane (XY plane), and the arm 43 inserts the
substrate P into the chamber 40. The first opening 41, into which
the arm 43 for holding the substrate P adhered with the liquid 50
is inserted, is formed on the lower side in the Z axis direction as
compared with the second opening 42. The arm 43 transports the
substrate P with the frontward side in the inserting direction with
respect to the chamber 40 (frontward side in the transport
direction) being directed upwardly.
[0126] The arm 43 moves the substrate P with respect to the first
and second blow sections 33, 34 in a state in which the inclination
of the substrate P is maintained. The first and second blow
sections 33, 34 allow the gas to blow against the moving substrate
P. The liquid 50, which is adhered to the substrate P, is removed
by the gas blow. In this procedure, the substrate P is inclined.
Therefore, the liquid 50 is easily moved by its self-weight toward
the lower side in the direction of inclination of the substrate P.
The removal of the liquid 50 from the substrate P is facilitated.
The liquid 50, which is removed from the substrate P, stays in the
chamber 40, and the liquid 50 is recovered by the liquid-sucking
unit 29 as the recovery unit. Alternatively, the liquid 50 may be
moved by the self-weight toward the downward side in the direction
of inclination of the substrate P in a state in which the substrate
P is inclined, and the gas may be allowed to blow against the
liquid 50 collected on the downward side in the direction of
inclination. Further alternatively, the drying operation as
described above may be simultaneously used. That is, when the
liquid is removed with the liquid-removing unit 100, it is also
allowable to use any one of the methods of the rotation of the
substrate P, the inclination of the substrate P, the sucking
operation, the drying operation, and the gas-blowing operation
(liquid-blowing off operation), or it is also allowable to
appropriately combine them.
[0127] One end of the substrate P from which the liquid 50 has been
removed protrudes to the outside of the chamber 40 from the second
opening 42. An arm (second transport member) 44, which serves as a
third transport unit H3, is provided in the vicinity of the second
opening 42. The substrate P, from which the liquid 50 has been
removed, is directly delivered from the arm 43 to the arm 44.
[0128] This embodiment has been explained such that the substrate P
is transported while being inclined when the substrate P is
inserted into the chamber 40. However, the substrate P, to which
the liquid 50 is adhered, may be transported at any position other
than those disposed in the chamber 40 in a state in which the
substrate P is inclined by a predetermined angle with respect to
the horizontal plane. Accordingly, the liquid 50 adhered to the
substrate P falls from the substrate P by the self-weight. In this
case, a recovery unit, which recovers the liquid 50 separated from
the substrate P by the self-weight, is provided in the transport
passage. The angle of inclination with respect to the horizontal
plane, which is used when the substrate P is transported, can be
arbitrarily established, which may be 90 degrees. That is, it is
also possible to transport the substrate P in a state in which the
substrate P is allowed to stand vertically.
[0129] In the respective embodiments described above, it is
preferable that the surfaces of the arm 43 and the second transport
unit H2 for transporting the substrate P to which the liquid 50 is
adhered are liquid-repellent. Accordingly, even if the liquid 50
adhered to the substrate P is adhered to the second transport unit
H2 (arm 43) when the substrate P is transported, the liquid 50 can
be immediately and easily removed from the second transport unit H2
(arm 43). Therefore, it is possible to avoid the occurrence of such
an inconvenience that the liquid 50 adhered to the second transport
unit H2 (arm 43) is adhered (adhered again) to the substrate P. The
liquid-repelling treatment (water-repelling treatment) for making
the surface of the second transport unit H2 (arm 43) to be
liquid-repellent includes, for example, a coating treatment in
which a material having liquid repellence is used. The material
having the liquid repellence includes, for example, fluorine-based
compounds, silicon compounds, and synthetic resins such as
polyethylene and acrylic resins. The thin film, which is to be used
for the surface treatment, may be a single layer film or a film
composed of a plurality of layers. The liquid-repelling treatment
may be applied to the entire surface of the second transport unit
H2 (arm 43), or the liquid-repelling treatment may be applied to a
part thereof.
Seventh Embodiment
[0130] In the embodiment having been explained with reference to
FIG. 11, the substrate P is transported while being inclined, or
the substrate P is inclined in the liquid-removing unit 100
provided at the intermediate position of the transport passage.
However, as shown in FIG. 12, the liquid 50 may be removed by
inclining a substrate stage PST (Z stage 51) which holds the
substrate P adhered with the liquid 50, after completing the
exposure for the substrate P and before transporting (unloading)
the substrate P. With reference to FIG. 12, the substrate stage PST
(Z stage 51) holds the substrate P at a substantially central
portion of the upper surface. An annular liquid recovery port
(recovery groove) 73 capable of recovering the liquid 50 is formed
around the substrate P. A liquid-absorbing member 71 is arranged in
the recovery groove 73. A flow passage, which has one end connected
to the recovery groove 73 and which has the other end connected to
a liquid recovery mechanism provided outside the Z stage 51, is
formed in the Z stage 51. The liquid recovery mechanism includes,
for example, a vacuum system (suction unit) such as a vacuum pump,
and a tank for storing the recovered liquid. The liquid-absorbing
member 71 is composed of, for example, a porous material such as
porous ceramics and sponge, which is capable of retaining a
predetermined amount of the liquid 50. An annular auxiliary plate
79, which has a predetermined width to surround the outer
circumference of the substrate P, is provided between the substrate
P held by the Z stage 51 and the liquid-absorbing member 71
(recovery groove 73). The surface height of the auxiliary plate 79
is set to be approximately coincident with the surface height of
the substrate P held by the Z stage 51. The liquid-absorbing member
71 (recovery groove 73), which is arranged with the predetermined
width to surround the outer circumference of the auxiliary plate
79, plays a role to absorb (recover) the liquid 50 having been
incompletely recovered by the liquid recovery unit 2. With
reference to FIG. 12, a movement mirror 54X, which extends in the Y
axis direction, is provided at the end on the +X side of the Z
stage 51, and a movement mirror 54Y, which extends in the X axis
direction, is provided at the end on the Y side. Laser
interferometers radiate laser beams onto the movement mirrors 54X,
54Y to detect the positions of the substrate stage PST in the X
axis direction and in the Y axis direction.
[0131] The Z stage 51 is inclined by a leveling mechanism provided
for the Z stage 51 before the substrate P is transported (unloaded)
from the Z stage 51 (substrate stage PST) shown in FIG. 12 after
the completion of the exposure for the substrate P. Accordingly,
the substrate P, which is placed on the Z stage 51, is also
inclined. By doing so, the liquid 50, which remains on the
substrate P after the completion of the exposure, flows to the
recovery groove 73 so that the liquid 50 is recovered in accordance
with the action of the gravity (self-weight). When the operation
for inclining the Z stage 51 is performed as the operation for
recovering the liquid before the transport after the completion of
the exposure, for example, if it is feared that the tip portion of
the projection optical system PL may contact with the Z stage 51
(substrate P) as a result of the inclination of the Z stage 51,
then the Z stage 51 (substrate stage PST) may be retracted from the
position just under the projection optical system PL, and the
inclining operation may be performed at a position separated from
the projection optical system PL. In this embodiment, the substrate
stage and the inclination control thereof function as the
liquid-removing unit.
[0132] In the embodiment described above, the liquid on the
substrate P is removed by inclining the substrate P in accordance
with the inclination of the substrate stage PST (Z stage 51).
However, as disclosed in Japanese Patent Application Laid-open No.
1-214042, when a substrate support member, which is movable
upwardly and downwardly while holding the substrate P in order to
load and unload the substrate P, is carried on the substrate stage
PST, the substrate P may be inclined in accordance with the
inclination of the substrate support member. The substrate P may be
dried by allowing the dry air or the warm air to blow thereagainst,
before the substrate P is exported from the substrate stage PST.
That is, when the liquid is removed before the substrate P is
exported from the substrate stage PST, it is also allowable to use
any one of the methods of the rotation of the substrate P, the
blowing off of the liquid, the suction of the liquid, the
inclination of the substrate P, and the drying by allowing the gas
to blow, or it is also allowable to appropriately combine and use
them.
Eighth Embodiment
[0133] Next, an explanation will be made with reference to FIG. 13
about an exposure apparatus according to an eighth embodiment of
the present invention. This embodiment is characterized in that the
liquid-removing unit 100 is provided, and a washing unit 150, which
washes the substrate P after the exposure process with a washing
liquid, is provided at an intermediate position of the transport
passage between the main body of the exposure apparatus EX and the
liquid-removing unit 100. In this embodiment, the main body of the
exposure apparatus is constructed in the same manner as in the
first embodiment except that the single substrate stage PST is
used.
[0134] With reference to FIG. 13, the washing unit 150 includes a
chamber 151, and a washing liquid supply unit 152 which is provided
in the chamber 151 and which supplies the washing liquid to the
substrate P transported into the chamber 151. The washing liquid
supply unit 152 supplies the washing liquid to the upper surface
and the lower surface of the substrate P respectively. The chamber
151 is provided with a first opening 153 which is open on the side
of the main body of exposure apparatus EX and a second opening 154
which is open on the side of the liquid-removing unit 100. The
first and second openings 153, 154 are provided with shutters 153A,
154A which open/close the first and second openings 153, 154
respectively. The substrate P after the exposure process performed
by the main body of exposure apparatus EX is transported by a fifth
transport unit (not shown) via the first opening 153 into the
chamber 151 of the washing unit 150. A holding unit for holding the
substrate P is provided in the chamber 151. The substrate P is
subjected to the washing process with the washing liquid in a state
of being held by the holding unit. The substrate P, which has been
subjected to the washing process, is transported to the
liquid-removing unit 100 by the second transport unit H2. The
liquid-removing unit 100 removes the washing liquid adhered to the
substrate P.
[0135] In the present invention, any liquid other than water can be
used as the liquid 50 for the exposure process performed by the
main body of exposure apparatus EX based on the liquid immersion
method. In this embodiment, a fluorine-based oil is used as the
liquid 50. For example, when the light source of the exposure light
beam EL is the F.sub.2 laser, the F.sub.2 laser beam is not
transmitted through water. Therefore, the exposure process can be
performed by using the fluorine-based oil as the liquid 50 through
which the F.sub.2 laser beam is transmissive. As described above,
it is possible to use, as the liquid 50, those other than water.
Alternatively, for example, it is also possible to use, as the
liquid 50, cedar oil which has the transmittance with respect to
the exposure light beam EL, which has the refractive index as high
as possible, and which is stable against the photoresist applied to
the surface of the substrate P and the projection optical system
PL. When the liquid other than water is used as the liquid 50, the
liquid-removing process can be performed after performing the
washing process for the substrate P with the washing unit 150. As
described above, when the substrate P is washed, it is possible to
wash out, for example, foreign matters adhered to the substrate P
during the liquid immersion exposure or during the transport of the
substrate P. The removal of the liquid is performed smoothly
thereafter. It is possible to feed, from the exposure apparatus,
the clean substrate P to which the liquid and the foreign matters
are not adhered.
[0136] Any one of the liquid-removing units 100 provided for the
exposure apparatuses according to the first to sixth embodiments
may be used as the liquid-removing unit 100. The washing of the
substrate P and the removal of the liquid adhered to the substrate
P may be performed at an identical place. For example, the washing
and the liquid removal may be performed in the chamber 25.
Ninth Embodiment
[0137] Next, an explanation will be made with reference to FIG. 14
about an exposure apparatus and a device-producing system according
to a ninth embodiment of the present invention. This embodiment is
characterized in that a liquid-processing mechanism 160, which
processes the liquid fallen from the substrate P after the
exposure, is provided under a transport passage of a transport
system H for transporting the substrate P to the liquid-removing
unit 100. In this embodiment, two substrate stages PST1, PST2 are
provided, and the main body of the exposure apparatus is equivalent
to that described in the first embodiment.
[0138] With reference to FIG. 14, the liquid-processing mechanism
160 includes a gutter member 161 which is arranged under the
transport passage of the transport system H, and a liquid-sucking
unit 162 which discharges, from the gutter member 161, the liquid
50 recovered by the gutter member 161. In this embodiment, the
gutter member 161 is provided between the substrate stage PST
(PST1, PST2) and the liquid-removing unit 100, i.e., under the
transport passage of the second transport unit H2. The gutter
member 161 is provided in a chamber unit CH1, and the
liquid-sucking unit 162 is provided outside the chamber unit CH1.
The gutter member 161 is connected to the liquid-sucking unit 162
via a tube passage 163. The tube passage 163 is provided with a
valve 163A which opens/closes the flow passage of the tube passage
163.
[0139] There is such a possibility that the liquid 50 may fall from
the substrate P during the transport of the substrate P to which
the liquid 50 is adhered after the exposure by using the second
transport unit H2. The fallen liquid 50 can be recovered with the
gutter member 161. When the fallen liquid 50 is recovered with the
gutter member 161, for example, it is possible to avoid such an
inconvenience that the liquid 50 is scattered to the surroundings
of the transport passage. The liquid-sucking unit 162 sucks the
liquid 50 on the gutter member 161 provided in the chamber unit
CH1, and thus the liquid 50 is discharged to the outside of the
chamber unit CH1 and the liquid 50 cannot stay on the gutter member
161 in the chamber unit CH1. It is possible to avoid any
inconvenience which would be otherwise caused such that the
humidity change (environmental change) occurs in the chamber unit
CH1. The liquid-sucking unit 162 can continuously perform the
operation for sucking the liquid 50 recovered by the gutter member
161. Alternatively, the liquid-sucking unit 162 can intermittently
perform the sucking operation in only a preset predetermined
period. When the sucking operation is continuously performed, the
liquid 50 does not stay on the gutter member 161. Therefore, it is
possible to more reliably avoid the humidity change in the chamber
unit CH1. On the other hand, when the sucking operation (discharge
operation) by the liquid-sucking unit 162 is not performed, for
example, during the exposure for the substrate P by the main body
of exposure apparatus EX, and the sucking operation is performed in
only the period other than the exposure, then it is possible to
avoid any inconvenience which would be otherwise caused such that
the vibration, which is generated by the sucking operation, affects
the exposure accuracy.
[0140] It is desirable that the gutter member 161 is provided over
an entire area under the transport passage for transporting the
substrate P which has a possibility of adhesion of the liquid.
However, the gutter member 161 may be provided partially and/or
separately at any place which tends to be affected by the liquid
fallen from the substrate P. The liquid-processing mechanism 160,
which is disposed under the transport passage, is not limited to
the gutter member 161 and the liquid-sucking unit 162. It is also
allowable to adopt any system capable of recovering the liquid
fallen from the substrate P or the like.
[0141] Any liquid-removing unit 100, which is provided for any one
of the exposure apparatuses according to the first to sixth
embodiments, may be employed as the liquid-removing unit 100. It is
also possible to provide, in the transport passage, the washing
unit as used in the first to sixth embodiments.
[0142] In the embodiment described above, the liquid-removing unit
100 is provided in order to remove the liquid which cannot be
completely recovered by the liquid recovery unit 2 and which
adheres to (remains on) the substrate P. However, it is not
necessarily indispensable to provide the liquid recovery unit
2.
[0143] The substrate P, which is usable in the respective
embodiments described above, is not limited to the semiconductor
wafer for producing the semiconductor device. Those applicable
include, for example, the glass substrate for the display device,
the ceramic wafer for the thin film magnetic head, and the master
plate (synthetic quartz, silicon wafer) for the mask or the reticle
to be used for the exposure apparatus.
[0144] The embodiment described above adopts the exposure apparatus
in which the space between the projection optical system PL and the
substrate P is locally filled with the liquid. However, the present
invention is also applicable to the liquid immersion exposure
apparatus in which the stage for retaining the exposure objective
substrate is moved in the liquid bath and the liquid immersion
exposure apparatus in which the liquid pool having the
predetermined depth is formed on the stage and the substrate is
retained therein. The liquid immersion exposure apparatus in which
the stage for retaining the exposure objective substrate is moved
in the liquid bath is disclosed in detail, for example, in Japanese
Patent Application Laid-open No. 6-124873, and the liquid immersion
exposure apparatus in which the liquid pool having the
predetermined depth is formed on the stage and the substrate is
retained therein are disclosed in detail, for example, in Japanese
Patent Application Laid-open No. 10-303114 and U.S. Pat. No.
5,825,043. These patent documents are incorporated herein by
reference within a range of permission of the domestic laws and
ordinances of the state designated or selected in this
international application.
[0145] As for the exposure apparatus (main body of the exposure
apparatus) EX, the present invention is applicable to the scanning
type exposure apparatus (scanning stepper) based on the
step-and-scan system for performing the scanning exposure for the
pattern of the mask M by synchronously moving the mask M and the
substrate P as well as the projection exposure apparatus (stepper)
based on the step-and-repeat system for performing the full field
exposure for the pattern of the mask M in a state in which the mask
M and the substrate P are allowed to stand still, while
successively step-moving the substrate P. The present invention is
also applicable to the exposure apparatus based on the
step-and-stitch system in which at least two patterns are partially
overlaid and transferred on the substrate P.
[0146] As for the type of the exposure apparatus EX, the present
invention is not limited to the exposure apparatus for the
semiconductor production apparatus for exposing the substrate P
with the semiconductor device pattern. The present invention is
also widely applicable, for example, to the exposure apparatus for
producing the liquid crystal display device or for producing the
display as well as the exposure apparatus for producing, for
example, the thin film magnetic head, the image pickup device
(CCD), the reticle, or the mask.
[0147] When the linear motor is used for the substrate stage PST
and/or the mask stage MST, it is allowable to use any one of those
of the air floating type based on the use of the air bearing and
those of the magnetic floating type based on the use of the
Lorentz's force or the reactance force. Each of the stages PST, MST
may be either of the type in which the movement is effected along
the guide or of the guideless type in which no guide is provided.
An example of the use of the linear motor is disclosed in U.S. Pat.
Nos. 5,623,853 and 5,528,118, contents of which are incorporated
herein by reference within a range of permission of the domestic
laws and ordinances of the state designated or selected in this
international application.
[0148] As for the driving mechanism for each of the stages PST,
MST, it is also allowable to use a plane motor in which a magnet
unit provided with two-dimensionally arranged magnets and an
armature unit provided with two-dimensionally arranged coils are
opposed to one another, and each of the stages PST, MST is driven
by the electromagnetic force. In this arrangement, any one of the
magnet unit and the armature unit may be connected to the stage
PST, MST, and the other of the magnet unit and the armature unit
may be provided on the side of the movable surface of the stage
PST, MST.
[0149] The reaction force, which is generated in accordance with
the movement of the substrate stage PST, may be mechanically
released to the floor (ground) by using a frame member so that the
reaction force is not transmitted to the projection optical system
PL. The method for handling the reaction force is disclosed in
detail, for example, in U.S. Pat. No. 5,528,118 (Japanese Patent
Application Laid-open No. 8-166475), a content of which is
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application. The reaction force,
which is generated in accordance with the movement of the mask
stage MST, may be mechanically released to the floor (ground) by
using a frame member so that the reaction force is not transmitted
to the projection optical system PL. The method for handling the
reaction force is disclosed in detail, for example, in U.S. Pat.
No. 5,874,820 (Japanese Patent Application Laid-open No. 8-330224),
a content of which is incorporated herein by reference within a
range of permission of the domestic laws and ordinances of the
state designated or selected in this international application.
[0150] As described above, the exposure apparatus EX according to
the embodiment of the present invention is produced by assembling
the various subsystems including the respective constitutive
elements as defined in claims so that the predetermined mechanical
accuracy, the electric accuracy, and the optical accuracy are
maintained. In order to secure the various accuracies, those
performed before and after the assembling include the adjustment
for achieving the optical accuracy for the various optical systems,
the adjustment for achieving the mechanical accuracy for the
various mechanical systems, and the adjustment for achieving the
electric accuracy for the various electric systems. The steps of
assembling the various subsystems into the exposure apparatus
include, for example, the mechanical connection, the wiring
connection of the electric circuits, and the piping connection of
the air pressure circuits in correlation with the various
subsystems. It goes without saying that the steps of assembling the
respective individual subsystems are performed before performing
the steps of assembling the various subsystems into the exposure
apparatus. When the steps of assembling the various subsystems into
the exposure apparatus are completed, the overall adjustment is
performed to secure the various accuracies as the entire exposure
apparatus. It is desirable that the exposure apparatus is produced
in a clean room in which, for example, the temperature and the
cleanness are managed.
[0151] As shown in FIG. 15, the microdevice such as the
semiconductor device is produced by performing, for example, a step
201 of designing the function and the performance of the
microdevice, a step 202 of manufacturing a mask (reticle) based on
the designing step, a step 203 of producing a substrate as a base
material for the device, an exposure process step 204 of exposing
the substrate with a pattern of the mask by using the exposure
apparatus EX of the embodiment described above, a step of
assembling the device (including a dicing step, a bonding step, and
a packaging step) 205, and an inspection step 206.
[0152] According to the present invention, it is possible to avoid
the change of the environment for the exposure process and the
scattering of the liquid to the surroundings. Therefore, it is
possible to avoid the decrease in the exposure process accuracy
which would be otherwise caused by the environmental change and the
liquid scattering, and it is possible to produce the device having
desired performance. The substrate, to which the liquid and the
foreign matters are not adhered, can be fed from the exposure
apparatus. Therefore, it is possible to produce the device having
desired performance.
* * * * *